This invention relates generally to the testing of liquids and more particularly to a unique testing apparatus for quantitatively determining (i.e., measuring) the activity or characteristic known as creepability of liquids, especially tracer liquids, such as penetrants and fluorescent leak tracers.
The creepability (or spreadability) function of liquids containing surfactants or wetting agents which are used to lower the surface tension of penetrating-type solutions can be defined as the spontaneous mobility of a liquid as it spreads or wets the surface of a material. This function or phenomenon which is known in the penetrant inspection art as "creepability" is actually capillarity acting as it is exposed travelling on the surface of an object. Here the front of the spreading film preferentially tends to travel at a much higher speed when it encounters scratches, cracks, tight grooves, parts tightly pressed together and the like, whether they are metallic or nonmetallic.
Unfortunately, there is no means available in the prior art for quantitatively determining the aforedescribed creepability, despite the fact that there is and has been a long-felt need for such a means.
The availability of such a means would result in significant benefits to the art, such as: providing the capability of improving, or of attempting to improve, the penetration action of or creepability of penetrants and leak tracers; permitting the checking of the stability of such formulations after they have been stored or used; allowing the checking of the consistency (or quality) of a given penetrant or leak tracer solution of subsequent batches of the penetrant or leak tracer from a manufacturer's and/or from a user's standpoint; and providing the capability of selecting a penetrant or liquid solution with the highest creepability when creepability is a vitally sought characteristic, such as in a leak tracer solution.
Accordingly, what is needed in the art, and is not presently available, is the aforesaid means for quantitatively measuring creepability.